The present invention relates to an electric machine and to a method for determining a position of a first active part of an electric machine relative to a second active part of the electric machine.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
In electric machines a first active part can usually be moved relative to a second active part. The exact determination of the position of the first active part relative to the second active part is of particular importance both in rotary electric machines and in linear motors. Firstly, in electric machines embodied as three-phase servo motors, if the position of the first active part relative to the second active part is precisely known the magnetic field of the electric machine can be adjusted particularly effectively such that as little total current as possible is required to generate a desired torque or advance force.
In electric machines embodied as a linear motor, a precise knowledge of the position of a primary part relative to a secondary part is necessary in order to permit an effective linear motion of the motor. Such linear motors or linear drives are normally used in machine tools or in production systems. Here too, very exact position control is normally also required.
It would be desirable and advantageous to obviate prior art shortcomings and to enable a determination of a position of a first active part of an electric machine relative to a second active part of the electric machine in a particularly effective manner.